Sell by. Use by. Best before. Lots of phrases appear on food labels, and it’s often unclear what they mean.

“People think that the dates on food are telling them to throw the food out,” says Dana Gunders, director of ReFED, a nonprofit dedicated to reducing food waste.

She says that in many cases, companies actually use date labels to indicate when a product is at its very best.

“They’re really trying to guarantee when their brand is at its top quality, when it’s freshest, but not that if you eat the product after that date you’ll get sick or it’s going to go bad,” Gunders says.

She says this misunderstanding leads to a lot of waste, which costs money and contributes to global warming.

It means more food is grown, transported, and refrigerated than needed — which creates carbon pollution.

And when food rots in a landfill, it releases methane, a potent global warming gas.

So Gunders’s group is pushing for passage of a federal bill to regulate date labeling.

It would establish one standard phrase to indicate when food is at its highest quality, and another to identify the date after which safety is a concern.

She says making this distinction clear could prevent confusion and help limit global warming pollution.

Reporting credit: Sarah Kennedy/ChavoBart Digital Media